CreateObjcBlockPointerFromHandler

Type

handler

Summary

Create an Objective-C block pointer that wraps an LCB handler.

Syntax

CreateObjcBlockPointerFromHandler(<pHandler>,<rBlockPtr>)

Description

Use the CreateObjcBlockPointerFromHandler handler to create a pointer to an Objective-C block that wraps an LCB handler. The block pointer can be used in calls to Objective-C foreign functions that expect a block as a parameter.

The wrapped handler will be called whenever the block is invoked, with the first parameter of its signature being the block pointer. The remaining parameters should match those of the Objective-C block.

The lifetime of a created ObjcBlockPointer is not automatically managed. When such a value has no more references to it and it is no longer going to be used, DeleteObjcBlockPointer should be used to free the resources used by it.

Parameters

Name	Type	Description
pHandler		The handler the block pointer should wrap.
rBlockPtr		The variable into which the block pointer should be returned.

Examples

private variable sRequestPermissionsCompletionHandler as optional ObjcBlockPointer
private variable sTarget as ScriptObject

public handler AudioLibraryInitialize() returns Boolean
	if not CreateObjcBlockPointerFromHandler(RequestPermissionsCompletionHandler, sRequestPermissionsCompletionHandler) then
		put nothing into sRequestPermissionsCompletionHandler
		return false
	end if
	put the caller into sTarget
	return true
end handler

private foreign handler ObjC_AVCaptureDeviceRequestAccessForMediaType(in pMediaType as ObjcId, in pCompletionHandler as ObjcBlockPointer) \
	returns nothing \
	binds to "objc:AVCaptureDevice.+requestAccessForMediaType:completionHandler:"

public handler AudioLibraryRequestPermissions()
	unsafe
		ObjC_AVCaptureDeviceRequestAccessForMediaType(StringToNSString("soun"), sRequestPermissionsCompletionHandler)
	end unsafe
end handler

public handler RequestPermissionsCompletionHandler(in pBlock as ObjcBlockPointer, in pGranted as CBool)
	post "AudioLibraryRequestPermissionsCallback" to sTarget with [pGranted]
end handler

Related

handler: DeleteObjcBlockPointer